Leishmaniasis, a disease caused by protozoan parasites of the Leishmania spp., is one of the major public health problems currently affecting humanity. Therapeutic agents for this disease is either ineffective or toxic. The purpose of this work is to aid in the development of an effective, nontoxic treatment for leishmaniasis. The objective of this research was to isolate and characterize unique leishmanial enzymes (DNA polymerase) and to test promising antileishmanial compounds for toxicity against human CEM T4 cells. The need for leishmanicides cannot be overemphasized. At present chemotherapy is dependent on a relatively small number of synthetic drugs. Resistance has been reported to occur against all these drugs and development of resistance to one compound is often accompanied by cross resistance to others. In the chemotherapy of visceral and cutaneous leishmaniasis, the choice of drugs is very limited and success of a particular drug appears to vary from locality to locality, presumably due to strain differences in Leishmania.